<style>
    .topic {
        position: fixed;
        right: 10px;
        bottom: 10px;
        width: 200px;
        background: cornflowerblue;
        transition: 0.2s;
    }

    .input-container {
        width: 90%;
        margin: 10px auto;
    }

    .input-container input {
        width: 100%;
        background: none;
        outline: none;
        border: none;
        background: aliceblue;
        font-size: 12px;
    }

    .input-container input:focus {
        width: 100%;
        border: none;
    }

    .input-submit {
        text-align: center;
        color: white;
        background: coral;
        width: 60%;
        margin: 10px auto;
        border-radius: 5px;
        font-size: 12px;
        padding: 6px 0;
        cursor: pointer;
    }
</style>
<div class="topic">
    <div class="input-container"><input type="number" class="speed-input" placeholder="请输入调整的倍数" value="100"></div>
    <div class="input-submit" onclick="setVideoTime()">开始刷课时</div>
</div>